1. Field of the Invention
The present invention relates to a method for the quantitation and separation of contaminants from particulate materials. The present invention also relates to an apparatus and immobilized enzymes and antibodies useful for carrying out such methods.
2. Discussion of the Background
There are a number of industries in which the detection and/or quantitation of contaminants in particulate materials is important. For example, in the food industry the permissible amounts of contaminants, such as insect parts and air (collectively referred to as filth), is closely regulated. Typically, such contaminants are present in the starting materials (ingredients, such as sugar, cocoa, spices, flour, coffee, tea, rice, etc.) used in the preparation of prepared foods, such as baked goods, candies, batters, etc., or packaged for sale to the consumer. In addition, meats, cheeses, and spreads may be contaminated with, in addition to the contaminants described above, microorganisms, such as bacteria, including, e.g., Salmonella, Listeria, Campylobacter, other pathogenic bacteria and a variety of fungi. For the purposes of the present disclosure, the term particulate material includes even those foods and materials not usually thought of as being particulate, such as meats, cheeses, spreads, whole fruits and vegetables, milk and other dairy products, animal feeds, etc., when such foods have been ground, dispersed or pulped, etc.
Although current techniques exist for separating and quantitating such impurities in particulate foods, the existing techniques are characterized as being slow and cumbersome. For example, such methods involve a complex series of steps including various washings with organic solvents and rely ultimately on the floatation of the light filth. Typically, such methods require times on the order of hours, rather than minutes.
In particular, an ELISA assay for insect parts based on the detection of a specific insect muscle protein (myosin) has been reported in Milling & Baking News, Apr. 21, 1992, page 29, and in Kitto, Bulletin, Association of Operative Millers, March 1991, pp. 5835-5838, and U.S. Pat. No. 5,118,610. However, the laboratory version of this technique requires about 2.5 hours.
In addition, an assay for chitin is disclosed in U.S. Pat. No. 5,118,610. However, this assay relies on the digestion of chitin.
Because the existing techniques for separating and quantitating contaminants in particulate foods are slow, problems arise during the mass production and/or packaging of foods. For example, it may be necessary to shut down a production line while a batch of an ingredient is tested to see if it meets mandated purity standards. Moreover, it may be necessary to discard a batch of prepared and/or packaged food, if an ingredient used in the preparation of the batch is later found to contain an unacceptably high level of contaminants.
Another shortcoming of the existing techniques for separating and quantitating the level of contaminants in particulate foods is that these techniques are characterized as exhibiting a lack of accuracy and reproducibility. Results obtained from such techniques do not correlate well with the actual degree of contamination of the food.
In addition, cosmetics and personal care products, such as creams, powders, toothpastes, etc., may contain many of the same contaminants. Although such cosmetics are not so closely regulated as foodstuffs, this situation may change in the near future. In any event, it is desirable for public health as well as public relations purposes to detect and remove such contaminants from these products. However, the currently available methods for separating and quantitating such contaminants in cosmetics and cosmetic ingredients suffer from the same drawbacks and disadvantages discussed above in the context of foods.
Thus, it would be desirable to provide a method for separating and quantitating contaminants in particulate materials such as foods and cosmetics, etc., which is fast, efficient, and accurate, and gives reproducible and statistically valid results. It would also be desirable to provide an apparatus and reagents which would facilitate the implementation of such a method.